(a) Field of the Invention
The present invention relates to an insulated window frame of synthetic resin material and wherein the outer peripheral frame member is molded in one piece and has a fixed upper sash frame also molded integral therewith. The bottom sill molded with the outer peripheral frame is also provided with an integrally formed backsplash support wall which supports a moving window sash in an insulating manner and wherein all frame members are formed of plastics material for thermal insulation and to make the entire window substantially weatherproof.
(b) Description of Prior Art
Various window frame structures made of synthetic resin material are known. It is also known to construct these windows with snap-in attachment parts. However, in the majority of known window frame structures that are made of synthetic resin material, there are fasteners which extend through the outer frame, therefore exposing the fasteners to outside ambient temperatures, causing these fasteners to act as thermal conductors. Also, the majority of window frame structures constructed of synthetic resin material also utilize various other products such as metal or wood in combination with the resin material. In other words, the core of some of the elements may be wood or metal and these are covered with plastic strips. These are therefore costly to fabricate and often require fasteners in order to secure the core material to the outside covering. The metal cores also act as thermal conductors within the window frame and sashes.